RU2079444C1 - Method of cleaning water from petroleum derivatives and heavy metal ions - Google Patents

Abstract

FIELD: water purification. SUBSTANCE: invention can be applied for household and drinking water supply, especially under field conditions. According to the first version of proposed method, water to be cleaned is poured in into 8-10-l vessel through filtration charge containing two-layer filter composed of (from above downwards in direction of water flow) (i) clay zeolite (monoclinic clinoptilolite) layer with 10-15 vol % of montmorillonite, 95-98 mm high and having 1-3 and 4-5-mm fractions in 1:1 ratio, and (ii) filter-perlite layer 2-5 mm high and 0.01-0.1 mm particle size. 50-60 min later, filtration charge is removed and cleaned water drained. Cleaning effect consists in elevated capture of impurities and smells of petroleum derivatives and increase in removing zinc(II) and lead(II) ions. In addition, service life of filter is increased. According to the second version of invention, filtration charge is supplemented with third filter-perlite layer above zeolite layer having the same characteristics as lower layer. This version is recommended when water to be cleaned is strongly polluted with suspended particles and/or when filtration speed is lowered. Service life of filter is 1.5-2 times increased as compared to known method. EFFECT: increased purification degree and prolonged service life of filter. 2 cl, 3 dwg , 2 tbl

Description

 The invention relates to methods for purifying water from oil products, heavy metal ions, suspended particles by filtration, and can be used in drinking water supply in the absence of a water supply network, especially in field conditions or in rural areas.

. Однако, указанный способ не позволяет извлекать примеси ароматических нефтепродуктов и в недостаточной степени улавливает ионы Zn²⁺ и Pb²⁺, не пригоден для работы в полевых условиях, поскольку модифицированный цеолит достаточно быстро (через 2 месяца работы) насыщается, вследствие чего ухудшается его фильтрационные свойства [1]
Наиболее близким по технической сути и достигаемому эффекту является способ фильтрования питьевой воды, осуществляемый в серийно выпускаемом бытовом фильтре типа "Родничок", работающий по принципу пропускания воды через слой моноклинного, не содержащего примеси глинистых частиц, цеолита [2] К недостаткам относится слабое улавливание примесей и запахов ароматических нефтепродуктов и ионов тяжелых металлов Zn²⁺ и Pb²⁺, относительно малый срок службы фильтра, что не удовлетворяет работе в полевых условиях.A known method of purification of drinking water by filtration, in which the sorption filter load contains the following components (in volume.): Activated carbon in silver form 10-35; modified zeolite in sodium or potassium form 20-50 and activated carbon the rest. Modified zeolite has the following lattice parameters:

. However, this method does not allow to extract impurities of aromatic oil products and does not sufficiently capture the Zn ²⁺ and Pb ^{2+ ions} , is not suitable for work in the field, since the modified zeolite is saturated quite quickly (after 2 months of operation), as a result of which its filtration deteriorates properties [1]
The closest in technical essence and the achieved effect is the method of filtering drinking water, carried out in a commercially available household filter of the Rodnichok type, operating on the principle of passing water through a layer of monoclinic clay-free particles of zeolite [2] The disadvantage is poor capture of impurities and odors of aromatic petroleum products and heavy metal ions Zn ²⁺ and Pb ²⁺ , a relatively short filter life, which does not satisfy the work in the field.

The technical result obtained from the implementation of the present invention, improving the quality of water purification by increasing the amount of trapped impurities and the ability to capture odors of aromatic oil products (especially kerosene)), increasing the degree of purification from Zn ²⁺ and Pb ^{2+ ions} , as well as the filter life, which very important for field conditions.

 An additional technical result in the implementation of the second embodiment of the invention is increased purification from suspended particles and a change (decrease) in the filtration rate.

 The specified technical result is achieved by the fact that in the method of purifying water from oil products and heavy metal ions according to the first embodiment, comprising passing water through a layer of monoclinic zeolite, filtered water is additionally passed and settled for 50-60 minutes through a layer of filter perlite located below the zeolite along the course water, moreover, a monoclinic clinoptilolite containing 10-15% montmorillonite is chosen as zeolite, while two fractions of a neolith with grain sizes of 1-3 and 4-5 mm in a ratio of 1: 1 are used, filter rlit with a particle size of 0.01-0.1 mm, the height of the zeolite layer and filtroperlita (mm) 95-98 and 2-5 mm respectively, and the regeneration is carried out by its filtrozagruzki humidification for 24 hours.

 According to a second embodiment of the invention, a filter perlite layer located above the zeolite layer in the course of the water flow is additionally introduced into the filter charge, with the parameters of the fractions and the layer height being the same as those of the lower filter perlite layer, with the same sequence and mode of operation. The second option can be implemented if the water to be treated is heavily contaminated with suspended particles and / or the filtration rate should be reduced, for example, when taking water from ponds, rivers, and other open water bodies to use water as drinking water. In this case, water is passed through three cleaning layers according to the scheme: "upper layer of filter perlite zeolite - lower layer of filter perlite".

The authors found that by using the main difference between the claimed technical solutions and the prototype of a qualitatively new filtering feature according to the scheme: “natural clay zeolite filterroperlite”, an effect not described in the literature can be achieved that increases the capture of impurities and odors of aromatic petroleum products (especially kerosene, gasoline), an increase in the degree of purification from ions of Zn ²⁺ and Pb ²⁺ , as well as the service life of the filter several times in comparison with filtration through a layer of clay-free zeolite. In other words, the authors established a qualitatively new sign of filtration, using natural minerals without any modification, but close in structure, which provides an improved quality of water purification due not only to physical sorption (mechanical purification), but also to chemical sorption due to the diffusion of sorbed cations from zeolite to perlite. The rate of diffusion of cations from zeolite to perlite is much lower than the rate of diffusion of cations from water to zeolite, and the ion exchange capacity of perlite is higher compared to the ion exchange capacity of zeolite. Thus, filter perlite, as it were, produces a chemical purification of zeolite. If you use clay-free monoclinic zeolite, as in the prototype for example, then the diffusion of cations from the zeolite will not occur and chemical purification will also not occur. Therefore, with long-term filter service, there is a general deterioration in the quality of water treatment.

 The service life of the filter according to the prototype method is quite limited because it is determined by the capacity of a given amount of zeolite, the selective ability of which is limited in relation to a strictly defined group of metals. In the claimed methods, a very well-chosen scheme works: "natural clay zeolite filterroperlite" or "filterroperlite clay zeolite filterroperlite", due to the fact that montmorillonite, the main mineral with high sorption properties, is present in the monoclinic clinoptilolite aggregate.

 The presence of montmorillonite mineral skeleton-cellular structure gives the mixture a higher sorption properties than when using each mineral separately. Sorption of colloidal particles and oil products is observed.

 The addition of filter perlite dramatically improves the quality of cleaning solutions due to the effect of the interaction of filter perlite and zeolite that we have established. The effect is based on the proximity of the structure of these two components: filter perlite and zeolite. The zeolite is characterized by a "loose skeleton-cellular structure." Filter perlite consists of glass particles, in the molecular skeleton of which there is a “cell” with a structure similar to that of zeolite, which determines the ion-exchange ability of filter perlite. However, ion-exchange cations in pearlite glass are more strongly bound to the framework than is the case in zeolite; therefore, exchange reactions in filter perlite proceed more slowly. The authors found that with prolonged contact of zeolite and filter perlite under conditions of high humidity, ions diffuse from zeolite to filter perlite. As a result of these observations, the following scheme of the filtration process in the system was constructed: "zeolite-filterroperlite". At the first stage of filtration, the zeolite traps heavy metal cations, and in the filter perlite, mechanical sorption of suspended particles and large molecules of oil products is carried out. However, after the zeolite is saturated with heavy metal cations and loses its ability to sorb them, the diffusion of cations from zeolite to filter perlite begins. Due to the fact that the ion-exchange capacity of filter perlite is higher than that of zeolite, a kind of “purification” of zeolite from heavy metal cations occurs and its ion-exchange properties are restored. As a result, the filter life as a whole increases. Due to this, the filter, if it is in a wet state, can restore its filtration properties without changing the load after 24 hours. Thus, one filter load can serve 1.5-2 times longer (without replacement) than a filter consisting of one zeolite.

 The choice of fractions of zeolite 1-3 mm and 4-5 mm in a ratio of 1: 1 is due to the need to create the most dense packing of the filter medium. The particle size of filter perlite 0.01-0.1 mm provides a high sorption of suspended particles, oil products and colloids. The layer height of 2-5 mm for filter perlite and 98-95 mm for zeolite provides an adjustable filtration rate necessary for complete cleaning. The time for passing and settling water of 50-60 minutes ensures the filling of this tank and filtering.

 The implementation of the proposed methods is illustrated using the devices shown in figa, b.

 In FIG. 1a shows a device for implementing the method according to embodiment 1, where 1 a container for collecting purified water, 2 zeolite (a mixture of fractions 1-3 mm and 4-5 mm), 3 filter perlite, 4 cover with filter loading.

 In FIG. 1b shows a device for implementing the method according to option 2, where 1 a container for collecting purified water, 2 zeolite of the indicated fractions, 3 - filter perlite of the lower layer, 4 cover with filter loading, 5 filter perlite of the upper layer.

 In FIG. 2 shows a device for implementing the prototype method, where 1 is a container for filter loading, 2 zeolite, 3 cover with nozzles for supplying and discharging water, 4 hoses for supplying purified water, 5 hose for purified water.

In FIG. Figure 3 shows a graph of the purification of tap water from Zn ^{+ 2} and Pb ^{2+ ions} depending on the filtration time. The abscissa shows the concentration of metal ions c in mg / l, while the ordinate axis shows time τ in min. where curve 1 shows the change in the concentration of Zn ²⁺ at the initial concentration of Zn ^{2 -} 4,53 mg / l; on curve 2, the change in the concentration of Pb ²⁺ at the initial concentration of Pb ²⁺ 3.53 mg / l; on curve 3, the change in the concentration of Zn ²⁺ at the initial concentration of 0.091 mg / L.

 The graph shows that at high concentrations of metal ions, characteristic of industrial waters, it is possible to reduce the concentration of lead and zinc by 4 times within 20 minutes, and by filtering for 30 minutes by about 10 times. At low concentrations characteristic of natural water for 30 minutes, the concentration of lead and zinc decreases by 20 times and reaches the permissible limits for drinking water according to GOST.

In the table. 1 shows the results of filtering water contaminated with petroleum products and in particular kerosene. Kerosene stains occupied half or more of the space of the tank taken for testing (in from the surface area in cm ² ). The water had a sharp unpleasant odor. Filtering according to method 1 was carried out for 40 minutes The obtained filtrate was completely free from kerosene impurities, the smell was completely absent (Table 2).

 We have done hundreds of experiments on options 1 and 2, the results of which are summarized in table. one.

Example 1
The device of FIG. 1a (household filter for water purification) consists of a plastic container 1 (8-10 l), having dimensions: outer diameter of the bottom 160 mm, outer diameter of the top cover 300 mm, height 350 mm, diameter of the loading chamber 80 mm, height of the loading chamber 100 mm A removable cover is immersed in this container, made at the same time with a cylindrical recess for the load filter. A layer of filter perlite with a standard particle size of 0.01-0.1 mm (filter perlite of the Mytishchensky plant) 2-5 mm high is placed at the bottom of the cylinder, then a layer of monoclinic clinoptilolite of the Shyvyrtuysky deposit containing 10-15 volume is poured. montmorillonite with a layer of 95-98 mm, previously crushed into fractions of 1-3 mm and 4-5 mm and mixed in a ratio of 1: 1, then the lid with the filter is placed in a container 1, which is filled with purified water. The sedimentation and filtration was carried out for 50 to 60 minutes This procedure is repeated until the container is filled with purified water. For a complete regeneration of the filtration charge, the container is filled with water through the filter charge and kept for 24 hours. Tap water was passed through the aforementioned filter, into which heavy metal ions were added (in some cases with an initial concentration of Zn ²⁺ - 4.53 mg / l, in others - 0.091 mg / l), Pb ²⁺ with an initial concentration of 3.53 mg / l and lamp kerosene up to 50-80% of the surface being cleaned in cm ² . Weighed particles of 3-5 mg / L were also added. After 50-80 minutes of filtration, purified water was analyzed for the presence of heavy metal ions Zn ²⁺ and Pb ²⁺ , kerosene and its smell, and suspended particles. Purified water fully complies with GOST for drinking water.

 Example 2 (option 2).

The filtration and sedimentation process was carried out as in example 1, but the filter charge contains an upper layer of filter perlite with a particle size of 0.01-0.1 mm and a height of 4 mm For the experiment, water was taken, to a greater degree of pollution than in example 1. Tap water was passed through the aforementioned filter, in which heavy metal ions of zinc with an initial concentration were added (Zn ²⁺ 4.53 mg / L, Pb ²⁺ with an initial concentration 3.5 mg / l). The concentration of lamp kerosene was 80% of the surface of the base of the cylinder with an area of 12 cm ² , i.e. 9.6 cm ² , in addition, suspended particles with a size of less than 1 μm were added in an amount of 0.5% of the filter load (8- 10 mg / l). After 50-60 minutes of filtration, purified water was analyzed for the presence of heavy metal ions (Zn ²⁺ and Pb ²⁺ , kerosene, suspended particles). Purified water fully complies with the requirements of GOST for drinking water.

 Example 3 (prototype).

 The device of FIG. 2 (the Rodnichok household filter consists of a plastic case 1 having the shape of a truncated cone with a lower diameter of 70 mm and an upper diameter of 100 mm. The height of the cylinder is 200 mm. The top is closed by a cover 3 with two nozzles for untreated 4 and purified 5 water. Through tap 4 is supplied with tap water, purified water enters through pipe 5. The cylinder is charged with zeolite containing no clay particles, filtering takes place within 50 minutes, tap water contaminated with heavy metals was passed through this device lamas, lamp kerosene and suspended particles in the concentrations given in example 1.

 Analysis of the purified water showed that the cleaning process is not carried out completely. Kerosene remains in purified water, which is felt by a rather strong smell. The concentrations of heavy metals are higher by an order of magnitude for zinc and by 2 orders of magnitude for lead compared with the results obtained in option 1.

 It should be noted that during Rodnichka’s operation in the normal mode, filtration took place within 20 s, while sedimentation was practically absent, therefore, the quality of the treated water was still worse compared to those given in Table. 1 results (since water was continuously circulating through a zeolite filter).

 The results of the experiments are summarized in table. 1 and are shown in the graph (Fig. 3). As can be seen from the above results, the quality of the purified water by the proposed methods is significantly higher than that of the prototype, the normal operation period (without changing the filter load) of the proposed methods is also longer. The authors are not aware of filters for drinking water that would ensure such a quality of water purification, the service life of the device itself without replacing the filter load with sufficient cheapness of the method of use and devices. These methods are very effective for geologists, lumberjacks, etc.

Claims (2)

1. A method of purifying water from oil products and heavy metal ions, comprising filtering water through a layer of monoclinic zeolite, characterized in that the water is additionally passed and settled for 50-60 minutes through a layer of filter perlite located below the zeolite along the course of the water, as a source of zeolite take monoclinic clinoptilolite with a content of 10
15 about montmorillonite, moreover, fractions of zeolite with a size of 1 3 mm and 4 5 mm in a ratio of 1 1 are used, a fraction of filter perlite with a size of 0.01 0.1 mm with a layer height of zeolite and filter perlite of 95 98 mm and 2 5 mm, respectively, after settling purified water is drained and the regeneration of the filtration charge is carried out by wetting it for 24 hours  2. A method of purifying water from oil products and heavy metal ions, comprising filtering water through a layer of monoclinic zeolite, characterized in that the water is additionally passed and settled for 50-60 minutes through two layers of filter perlite with the same parameters, located one layer above and below the zeolite along the course of the water, a monoclinic clinoptilolite with a content of 10 15 vol. montmorillonite, moreover, a fraction of zeolite with a size of 1 3 mm and 4 5 mm is used in a ratio of 1 1, filter perlite is 0.01 0.1 mm, with a layer height of zeolite and filter perlite is 95 98 mm and 2 5 mm, respectively, after settling the purified water is drained, and the regeneration of the filtration charge is carried out by wetting it for 24 hours

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